Signaling system



G. w. JANsoN SIGNALING SYSTEM Filed Jan.` 2e, 1952 April 10, 1934.

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Patented Apr. 10,1934

UNITED STATES PATENT OFFICE SIGNALING SYSTEM Application January 26, 1932, Serial No. 588,994

Claims. (Cl. 178--4.1)

This invention relates to signaling systems of the type wherein a plurality of lines terminate at a central oflice and while particularly intended for systems employing telegraph printers of the 5 start and stop type, such as the Well-known simpleX printers, it is also applicable to other signaling systems.

Single current telegraph circuits in this country are normally closed, With line current flowing during idle time, in order to keep'the line available for signals from either end. In some foreign countries, zero current during idle timeY is obtained, but at the expense of providing a line battery at each sending station.

The object of the present invention is to obtain, in a single current telegraph circuit, the advantage of zero line current during idle time without sacriiicing the advantages of closed circuit operation. To this end I insert an asymmetric device, such as a rectiiier element, in the line at the outer or branch oice.V This element is so poled that it permits the operating current to pass, but prevents the flow of current from a generator of opposite polarity applied during idle This system is, in effect, an open circuit line, but which may be closed for signaling by direct current from either end, viz: by shortcircuiting the rectifier at the outer branch ofce or by reversing the polarity of the generator at the central oiiice. L

A change of polarity at the central office, either when initiating or when answering a call, places the outer oflice instruments under the direct control of the central oflice. The outer oilice can signal the central office at any time by shortcircuiting the rectifier, thus providing a direct current path for the signaling generator. The line can be tested at any time by connecting the polarity of current which is passed by the rectiiier.

In the following detailed description I shall refer to the accompanying drawing in which, for the sake of convenience, the circuit arrangement is illustrated for only one branch office and only one simplex printer is shown at the central oiiice. The operators cord circuit and'its associated equipment at the central oiiice is substantially the same as that shown in U. S. Patent No. 1,804,327.

At the central office, the line L is connected through the line winding 5 of relay C to the multiple turret plugs 1, 2, 3, etc., rigidly located in front of the respective operators. A circuit is normally extended over each line from the central cnice to the branch on'ices, from the signal battery or generator SB through the winding of signal relay A, over conductor 31, outer right hand armature and back contact of relay B, conductor 30, line L, asymmetric element, such as a copper oxide rectier OX, at the outer branch oiiice, slow-to-release relay SL, printer magnet and normally closed printer contact to ground. No current flows over this circuit during idle periods as the rectifier element OX does not pass current from the positive pole of the generator SB which is normally connected to line.

The operator at the central oirice may signal the branch office by connecting her jack J to the plug associated with the branch office line, as described in the above mentioned patent. It this line is idle, relay D will be operated by virtue of the positive signaling battery SB being applied to the plate of vacuum tube VT. Operation of relay D closes a circuit through its locking winding to operate relays E and F. Operation of relay F starts the motor of printer SP2. Operation of relay E transfers the tip connection oi.' jaclr J from the plate ci VT to the printer and thus applies negative operating battery OB to the line L. The plate current of VT was insuflicient to operate relay C, but it is now operated by the increased current due to operating battery OB. Operation of relay C closes a circuit through its locking Winding 'I to operate relay B. Operation of relay B removes positive signaling battery SB from the line.

Negative operating battery OB is passed by the rectifier OX, thus operating relay SL at the branch cnice. Operation of relay SL closes a circuit from local battery v. to start the 90 printer motor M of branch oiiice printer SP1 and to light the signal lamp 40. The circuit is now ready for handling messages, with the motor M under control of the central oiiice operator.

The branch oiiice operator may call the ceng5 tral oiiice at any time by momentarily closing the switch K, thereby grounding the line ahead of the rectifier element OX. This causes current to iiow through the line from positive signaling battery SB, thereby operating signal relay A 1 0 and locking it, and lighting answer lamp 11 at the central cnice. In answering the call, the central oiiice operator connects her jack J to the appropriate line plug, thereby connecting negative operating battery OB to the line and re- 1(05 moving positive signaling battery, as was described in the preceding paragraphs. Relay A is unlocked by the operation of relay B, and in releasing extinguishes answer lamps 11. Negative operating battery, passed by the rectifier, llo

starts the branch ofce motor and lights the signal light as previously described, indicating to the branch oiiice operator that she may proceed with transmission.

During the transmission of signals, slow-torelease relay SL maintains the circuit of the printer motor M closed during the intervals between marking signals, when no current is flowing in the line.

When transmission is concluded, the central oflice operator withdraws her jack J from the line plug, removing operating battery OB from vthe line and deenergizing winding 5 of relay C. Relay SL at the branch oilice releases soon after the operating battery is removed, and stops the branch oiilce printer motor. Relay C does not release, however, until interrupter IR. opens the contact b, deenergizing locking winding '7 of relay C and winding 8 of relay B. Relay B does not release until interrupter IR opens contact a, deenergizing winding 9 of relay B. In falling back, relay B reconnects positive signaling battery to the line and prepares the locking circuit of relay A for the next call.

While I have described my invention as applied to the concentrator circuit and operators cord circuit shown in prior Patent 1,804,327, for purposes of illustration, it will be evident to engineers that other circuit arrangements may be employed. For instance, relay A could be made non-locking, a printer substituted for the busy lamps and a transmitter for the key K at the branch oflice. If a battery reversing switch, or other means of substituting one polarity for the other, is provided, the invention is applicable to single Morse circuits, or other systems which do not automatically reverse the battery. It may be used for selective signaling of telephone stations, and many other applications.

I claim:

l.. In combination, a signaling conductor, a receiving apparatus at one end, a potential source, a signaling device, and a transmitting apparatus at the other end, one polarity of said potential source being normally connected to said conductor, an asymmetric element associated with said receiving apparatus and adapted to prevent the passage of current of the polarity normally impressed upon said conductor, means for shunting said asymmetric element to operate said signaling device, and means for reversing the polarity of said source to permit the transmission of signals to said receiving apparatus.

2. In combination, a signaling conductor, a signaling device and a potential source at one end and means for reversing the polarity of the source connected to the conductor, a signaling device and an asymmetric element at the other end, said asymmetric element being interposed between the signaling device and the conductor, and means for shunting the asymmetric element and the last mentioned signaling device, to operate said iirst mentioned signaling device.

3. In a telegraph system, a printer line, a potential source normally connected with one polarity to the line and means for reversing the polarity of the source connected to the line, a printing unit and a driving motor therefor, a circuit for said motor, a relay connected to said printing unit and controlling said motor circuit, and a rectiier element interposed between said relay and said line permitting said relay and said printing unit to operate only upon a reversal of the normal line polarity.

4. A printing telegraph system comprising a plurality of stations, a line connecting said stations, a printing telegraph apparatus including a motor therefor and a call signal at one of said stations, a source of potential normally connected with one polarity to line at the other station and means for reversing the polarity of the line connection, a relay at said first station operating to effect the operation of said signal and the starting of said motor, and an asymmetric element interposed between said relay and the line permitting the ow of current of only a polarity opposite to the normal polarity.

5. A telegraph system comprising a plurality of stations, a line connecting said stations, an

electro-responsive device connected to the line at one station, a source of potential normally impressing one polarity on the line at another station, an asymmetric element interposed in the line between said electro-responsive device and said potential source to prevent the flow of a ics 

